The Experts below are selected from a list of 618 Experts worldwide ranked by ideXlab platform
Hans G. Lemij - One of the best experts on this subject based on the ideXlab platform.
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Structure-function relationship is stronger with enhanced corneal compensation than with variable corneal compensation in scanning laser polarimetry.
Investigative Opthalmology & Visual Science, 2007Co-Authors: Nicolaas J. Reus, Hans G. LemijAbstract:PURPOSE. To compare the structure-function relationship between peripapillary retinal nerve fiber layer (RNFL) retardation, measured with scanning laser polarimetry (SLP) with both enhanced and variable corneal compensation (ECC [enhanced corneal compensation] and VCC [variable corneal compensation], respectively; features of the GDx Nerve Fiber Analyzer; Carl Zeiss Meditec, Inc., Dublin, CA), and visual field (VF) sensitivity, measured with standard automated perimetry (SAP) in normal and glaucomatous eyes and the effect of marked atypical birefringence patterns (ABPs) on this relationship. METHODS. Thirty-three healthy subjects, and 68 patients with primary open-angle glaucoma (POAG) took part in the study. ECC and VCC images were taken in one randomly selected eye of each subject. VF tests were also obtained in the same eyes. The structure-function relationship was assessed in six peripapillary sectors and their matching VF areas and was reassessed after eliminating eyes with marked ABPs. RESULTS. Correlations (Spearman's correlation coefficients, r s ) in the structure-function relationship were generally stronger in images taken with ECC than in those taken with VCC. With ECC, the relationship was significantly more curvilinear when VF sensitivity was expressed in the standard Decibel Scale and more linear when VF sensitivity was expressed in an antilog Scale than with VCC. When eyes with marked ABP images were removed from the analysis, the structure-function relationship with VCC improved, and no statistically significantly differences were found in the relationships between VCC and ECC. CONCLUSIONS. The structure-function relationship between RNFL retardation and SAP VF sensitivity was stronger in images obtained with the GDx ECC than with the GDx VCC (Carl Zeiss Meditec, Inc., Dublin, CA). ABPs, which appeared more markedly with VCC than with ECC, weakened the structure-function relationship.
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the relationship between standard automated perimetry and gdx vcc measurements
Investigative Ophthalmology & Visual Science, 2004Co-Authors: Nicolaas J. Reus, Hans G. LemijAbstract:textabstractPURPOSE: To investigate the relationship between retinal light sensitivity measured with standard automated perimetry (SAP) and retardation of the peripapillary retinal nerve fiber layer (RNFL) measured with the GDx VCC (Laser Diagnostic Technologies, Inc., San Diego, CA). METHODS: Forty-seven healthy subjects and 101 patients with glaucoma were examined with SAP and with the commercially available scanning laser polarimeter GDx VCC, with automated individualized compensation of anterior segment birefringence. Individual visual field test points and peripapillary RNFL retardation measurements were grouped into six corresponding sectors. The correlation between perimetry and GDx VCC measurements was determined, and the relationship between RNFL retardation and perimetry, expressed both in the standard Decibel Scale and in an unlogged Scale, was described with linear regression analysis. RESULTS: A statistically significant correlation was found in most sectors between perimetry and GDx VCC measurements in patients with glaucoma, but not in healthy subjects. A linear relationship was found between the unlogged sensitivities and GDx VCC measurements for the superotemporal and inferotemporal sectors. In the Decibel Scale, this relationship was curvilinear. CONCLUSIONS: GDx VCC measurements of the peripapillary RNFL relate well with functional loss in glaucoma. Based on the observed relationships between function and structure, patients with mild to moderate visual field loss in glaucoma may be better monitored with the GDx VCC and patients who have severe loss, with SAP.
Nicolaas J. Reus - One of the best experts on this subject based on the ideXlab platform.
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Structure-function relationship is stronger with enhanced corneal compensation than with variable corneal compensation in scanning laser polarimetry.
Investigative Opthalmology & Visual Science, 2007Co-Authors: Nicolaas J. Reus, Hans G. LemijAbstract:PURPOSE. To compare the structure-function relationship between peripapillary retinal nerve fiber layer (RNFL) retardation, measured with scanning laser polarimetry (SLP) with both enhanced and variable corneal compensation (ECC [enhanced corneal compensation] and VCC [variable corneal compensation], respectively; features of the GDx Nerve Fiber Analyzer; Carl Zeiss Meditec, Inc., Dublin, CA), and visual field (VF) sensitivity, measured with standard automated perimetry (SAP) in normal and glaucomatous eyes and the effect of marked atypical birefringence patterns (ABPs) on this relationship. METHODS. Thirty-three healthy subjects, and 68 patients with primary open-angle glaucoma (POAG) took part in the study. ECC and VCC images were taken in one randomly selected eye of each subject. VF tests were also obtained in the same eyes. The structure-function relationship was assessed in six peripapillary sectors and their matching VF areas and was reassessed after eliminating eyes with marked ABPs. RESULTS. Correlations (Spearman's correlation coefficients, r s ) in the structure-function relationship were generally stronger in images taken with ECC than in those taken with VCC. With ECC, the relationship was significantly more curvilinear when VF sensitivity was expressed in the standard Decibel Scale and more linear when VF sensitivity was expressed in an antilog Scale than with VCC. When eyes with marked ABP images were removed from the analysis, the structure-function relationship with VCC improved, and no statistically significantly differences were found in the relationships between VCC and ECC. CONCLUSIONS. The structure-function relationship between RNFL retardation and SAP VF sensitivity was stronger in images obtained with the GDx ECC than with the GDx VCC (Carl Zeiss Meditec, Inc., Dublin, CA). ABPs, which appeared more markedly with VCC than with ECC, weakened the structure-function relationship.
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the relationship between standard automated perimetry and gdx vcc measurements
Investigative Ophthalmology & Visual Science, 2004Co-Authors: Nicolaas J. Reus, Hans G. LemijAbstract:textabstractPURPOSE: To investigate the relationship between retinal light sensitivity measured with standard automated perimetry (SAP) and retardation of the peripapillary retinal nerve fiber layer (RNFL) measured with the GDx VCC (Laser Diagnostic Technologies, Inc., San Diego, CA). METHODS: Forty-seven healthy subjects and 101 patients with glaucoma were examined with SAP and with the commercially available scanning laser polarimeter GDx VCC, with automated individualized compensation of anterior segment birefringence. Individual visual field test points and peripapillary RNFL retardation measurements were grouped into six corresponding sectors. The correlation between perimetry and GDx VCC measurements was determined, and the relationship between RNFL retardation and perimetry, expressed both in the standard Decibel Scale and in an unlogged Scale, was described with linear regression analysis. RESULTS: A statistically significant correlation was found in most sectors between perimetry and GDx VCC measurements in patients with glaucoma, but not in healthy subjects. A linear relationship was found between the unlogged sensitivities and GDx VCC measurements for the superotemporal and inferotemporal sectors. In the Decibel Scale, this relationship was curvilinear. CONCLUSIONS: GDx VCC measurements of the peripapillary RNFL relate well with functional loss in glaucoma. Based on the observed relationships between function and structure, patients with mild to moderate visual field loss in glaucoma may be better monitored with the GDx VCC and patients who have severe loss, with SAP.
Tzyy-ping Jung - One of the best experts on this subject based on the ideXlab platform.
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Estimation of alertness levels with changes in Decibel Scale wavelength of EEG during dual-task simulation of auditory sonar target detection
2010 Annual International Conference of the IEEE Engineering in Medicine and Biology, 2010Co-Authors: Saravana Pillai Arjunan, Dinesh K. Kumar, Tzyy-ping JungAbstract:Changes in alertness levels can have dire consequences for people operating and controlling motorized equipment. Past research studies have shown the relationship of Electroencephalogram (EEG) with alertness of the person. This research reports the fractal analysis of EEG and estimation of the alertness levels of the individual based on the changes in the maximum fractal length (MFL) of EEG. The results indicate that MFL of only 2 channels of EEG can be used to identify the loss of alertness of the individual with mean (inverse) correlation coefficient = 0.82. This study has also reported that using the changes in MFL of EEG, the changes in alertness level of a person was estimated with a mean correlation coefficient = 0.69.
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Changes in Decibel Scale wavelength properties of EEG with alertness levels while performing sustained attention tasks
2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2009Co-Authors: Saravana Pillai Arjunan, Dinesh K. Kumar, Tzyy-ping JungAbstract:Loss of alertness can have dire consequences for people controlling motorized equipment or for people in professions such as defense. Electroencephalogram (EEG) is known to be related to alertness of the person, but due to high level of noise and low signal strength, the use of EEG for such applications has been considered to be unreliable. This study reports the fractal analysis of EEG and identifies the use of maximum fractal length (MFL) as a feature that is inversely correlated with the alertness of the subject. The results show that MFL (of only single channel of EEG) indicates the loss of alertness of the individual with mean (inverse) correlation coefficient = 3D 0.82.
Saravana Pillai Arjunan - One of the best experts on this subject based on the ideXlab platform.
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Estimation of alertness levels with changes in Decibel Scale wavelength of EEG during dual-task simulation of auditory sonar target detection
2010 Annual International Conference of the IEEE Engineering in Medicine and Biology, 2010Co-Authors: Saravana Pillai Arjunan, Dinesh K. Kumar, Tzyy-ping JungAbstract:Changes in alertness levels can have dire consequences for people operating and controlling motorized equipment. Past research studies have shown the relationship of Electroencephalogram (EEG) with alertness of the person. This research reports the fractal analysis of EEG and estimation of the alertness levels of the individual based on the changes in the maximum fractal length (MFL) of EEG. The results indicate that MFL of only 2 channels of EEG can be used to identify the loss of alertness of the individual with mean (inverse) correlation coefficient = 0.82. This study has also reported that using the changes in MFL of EEG, the changes in alertness level of a person was estimated with a mean correlation coefficient = 0.69.
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Changes in Decibel Scale wavelength properties of EEG with alertness levels while performing sustained attention tasks
2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2009Co-Authors: Saravana Pillai Arjunan, Dinesh K. Kumar, Tzyy-ping JungAbstract:Loss of alertness can have dire consequences for people controlling motorized equipment or for people in professions such as defense. Electroencephalogram (EEG) is known to be related to alertness of the person, but due to high level of noise and low signal strength, the use of EEG for such applications has been considered to be unreliable. This study reports the fractal analysis of EEG and identifies the use of maximum fractal length (MFL) as a feature that is inversely correlated with the alertness of the subject. The results show that MFL (of only single channel of EEG) indicates the loss of alertness of the individual with mean (inverse) correlation coefficient = 3D 0.82.
Chan Kee Park - One of the best experts on this subject based on the ideXlab platform.
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comparative study of macular ganglion cell inner plexiform layer and peripapillary retinal nerve fiber layer measurement structure function analysis
Investigative Ophthalmology & Visual Science, 2013Co-Authors: Hyeyoung Shin, Haeyoung Lopilly Park, Kyoung In Jung, Chan Kee ParkAbstract:PURPOSE. We explored and compared the relationships between the visual field (VF) sensitivities assessed by standard automated perimetry (SAP), and the ganglion cell–inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (pRNFL) thicknesses as measured by Cirrus high-definition optical coherence tomography (HD-OCT) in glaucomatous eyes. METHODS. We enrolled 213 eyes of 213 patients with glaucoma. The thicknesses of the average/sectoral GCIPL and pRNFL were measured by Cirrus HD-OCT. The mean sensitivity (MS) of 24-2 SAP was recorded on Decibel and 1/L Scales. The topographic relationships between structure and function were investigated. RESULTS. Statistically significant correlations between the corresponding VF sensitivity and the macular GCIPL thickness were found in all GCIPL sectors. Among six GCIPL sectors, the strongest association was observed between superonasal center MS and inferotemporal GCIPL thickness. In comparative analysis, the association between the central cluster MS and average GCIPL thickness was significantly stronger than that of temporal pRNFL thickness using the Decibel Scale (P < 0.001). The association between regional VF sensitivities, and the inferior hemifield and inferior GCIPL thicknesses were significantly stronger than those of the corresponding pRNFL thickness using the Decibel Scale (P ¼ 0.001 and 0.007). CONCLUSIONS. The average and sectoral GCIPL thicknesses determined by Cirrus HD-OCT were associated significantly with global and regional VF sensitivity in patients with glaucoma. The macular GCIPL thickness values may provide more valuable information than temporal pRNFL thickness values for understanding the structure–function relationships of the macular region.
